Which sentence is correct in all its punctuation?

We believe that, our customer service effort must be a continuing process.

Realtors say three things are important in buying a home $($location$,$ location, location$).$

If you apply before the deadline $($January $1),$ you will beat the hiring freeze.

The troubleshooting section $($see pp$.1215$ of your owner$$s manual$),$ is very helpful.